Monopole and vortex dissociation and decay of the false vacuum

If monopole (or vortex) solutions exist for a metastable or false vacuum, a finite density of monopoles (or vortices) can act as impurity sites that trigger inhomogeneous nucleation and decay of the false vacuum. The monopoles (or vortices) become classically unstable and their cores expand radially, converting the volume of the system to the phase represented by the core of the monopole (or vortex). False vacuum decay about the monopole (or vortex) sites occurs for values of the barrier height and energy difference between the true and false phases that are insufficient for homogeneous bubble nucleation. Two cases where the phenomenon may play a role are phase transitions in early cosmology and in ³H-⁴He mixtures at low temperatures.